Clamping mechanism for road building machines or the like

ABSTRACT

Hydraulic clamping mechanisms automatically operative in response to the completion of adjustment of the circle and supported blade or moldboard of a road grader to rigidly clamp such structures in their adjusted positions so as to reduce wear and consequent inaccuracies in operation.

United States Patent lnventor Raymond A. Curries San Jose, Calif.

Appl. No. 852,990

Filed Aug. 25, 1969 Patented July 20, 1971 Assignee Gurries Manufacturing Co. San Jose, Calif.

CLAMPING MECHANISM FOR ROAD BUILDING MACHINES OR THE LIKE 4 Claims, 8 Drawing Figs. US. Cl 172/741, 172/763, 172/793 lut.Cl AOlb 35/22 1 E021 3/76 Field ofSearch 172/7, 763

l 56] References Cited UNITED STATES PATENTS 899,021 9/1908 Bayless 3,062,301 11/1962 Pomper 3,465,829 9/l 969 Fisher et al.

Primary Examiner-Robert Ev Pulfrey Assistant Examinen-Stephen C. Pellegrino Attorney-Paul B Fihe 172/763 X 172/7 X 172/793 X ABSTRACT: Hydraulic clamping mechanisms automatically operative in response to the completion of adjustment of the circle and supported blade or moldboard of a road grader to rigidly clamp such structures in their adjusted positions so as to reduce wear and consequent inaccuracies in operation.

PATENTED JUL 2 0 I971 SHEET 1 OF 3 INVENTOR RAYMOND A. EUR/PIES O ly. 6.

PATENT AGENT PATENTEB JUL20 i97| SHEET E OF 3 INVENTOR. RA YMO/VD A. Gum/5 m g EL.

PATENT AGENT PATENIEUJULZOISYI 3593806 SHEET 3 OF 3 INVENTOR. RA YMO/VD A. GURR/ES PATENT AGENT CLAMPING MECHANISM FOR ROAD BUILDING MACHINES OR THE LIKE BACKGROUND OF THE INVENTION The present invention relates generally to clamping mechanisms and more particularly to clamping mechanisms for rigidly holding adjustable elements of road building machines or the like in their adjusted positions.

It is, of course, well known that the working implement of various road building machines must be adjusted to meet the requirements ofa particular job. For example, in the case ofa road grader, the scraper blade or moldboard is conventionally mounted from the frame for a variety of adjustments from its generally horizontal, transversely disposed position. More particularly, the blade is mounted for elcvational adjustment, for cross-slope adjustment, for lateral sliding adjustment, and for rotational adjustment about both substantially vertical and horizontal axes. Conventionally, the rotational adjustment about the vertical axis is achieved by the turning of a circle in the form of a ringlike structure slidably supported for rotary movement and the lateral blade adjustment is achieved by lateral sliding movement of the blade upon its support. As will be obvious, a loose slidable fit must exist between the supporting member and the member slidably supported thereon and, as a consequence, a certain amount of wear exists during the adjustment of the members. More importantly,after the adjustment is complete, forces encountered during the grading operation effect limited vibrational motion of the blade resulting in additional wear of the supporting and supported members so that the loose slidable fit therebetween becomes more loose. This allows for variances in the precise disposition of the blade and resultant inaccuracy in the grading operation. It is to be expressly noted that the relatively movable supporting and supported members are lubricated to enable the requisite adjustments therebetween and in normal operation of the road grader, dust and dirt particles intermix with the lubricant to provide what is in actuality a very effective grinding compound which accelerates the wear on the opposed surface of the relatively movable supporting and supported elements. As a consequence, it has been found, as a practical matter, that after no more than one months use the accumulated wear is sufficient to produce an unacceptable shifting of the blade disposition from its desired level.

The problem of maintaining accuracy becomes particularly severe when the road grader is automatically controlled, for example, in the fashion described in detail in U.S. Pat. No. 3,346,976 issued Oct. 17, 1967 to John Curlett and Raymond A. Gurries wherein the blade disposition is controlled automatically relative to preestablished references which take the form of an external wire extending longitudinally of the path of movement of the road grader frame. lt will be apparent that the information sensed by such control mechanisms will in no way compensate for a change in blade disposition resultant from the wear of the blade supporting structures. When it is remembered that tolerances as small as one-eighth inch are now required in road grading operations, the inaccuracies resultant from continuing wear of the supporting elements cannot be tolerated, as a practical matter.

SUMMARY OF THE INVENTION ln view of the foregoing difficulties, it is a general objective of the present invention to provide a clamping mechanism arranged to hold the relatively movable supported elements for a road grader blade in rigid immovable relationship when in their adjusted dispositions. More particularly, opposed sur faces on the relatively movable elements are brought into clamped engagement when the adjusted disposition has been attained thus to hold the elements against movement during a grading operation wherefore frictional wear is eliminated and moreover the entry of dirt or other foreign material between such surfaces is precluded. It is preferred to establish such clamping engagement between opposed surfaces which normally are not in engagement during adjustment of the relatively movable elements. For example, if the supported element rests slidably on the supporting element thereunder during adjustment, the clamping action is achieved by slightly raising the supported element to bring an upper surface thereof into clamped engagement with an opposing surface on the supporting element. In this fashion, the level of the supported element and the blade carried thereby is consistently maintained when it its adjusted, operative disposition.

BRIEF DESCRIPTION OF THE DRAWINGS The forgoing general description of the clamping mechanism embodying the present invention can be understood more readily by reference to the following detailed description of the exemplary structures shown in the accompanying drawings wherein:

FIG. I is a side clcvational view ofa road grader embodying the invention,

FIG. 2 is a fragmentary bottom plan view as taken along line 2-2 of FIG. 1 illustrating one portion of the blade-blocking supporting structure,

FlG. 3 is a sectional view taken along the line 3-3 of FIG. 2,

FIG. 4 is an enlarged fragmentary sectional view of the 4-4 of FIG. 5,

FIG. 5 is a fragmentary view of the blade-supporting structure shown in FIG. 4 as viewed from the left thereof,

FlG. 6 is a diagrammatic view of the hydraulic circuit for actuating one clamping mechanism illustrated in FIGS. 2 and 3,

FlG. 7 is a similar diagrammatic illustration of the hydraulic circuit for actuating the clamping mechanism for the bladesupporting structure best illustrated in FlGS. 4 and 5, and

FIG. 8 is a perspective view of a control mechanism for the hydraulic adjustment and clamping mechanisms of the apparatus.

DESCRlPTlON OF THE PREFERRED EMBODIMENT With initial reference to FIG. I, the road grader, to which the present invention can be applied, is of generally conventional design including a rigid frame llll mounted at its rearward end on dual wheel units 12 that are driven from a con ventional diesel engine 14 mounted thereabove. The frame 10 extends forwardly in a somewhat arched configuration for support at its forward extremity on transversely spaced wheels 16 which can be steered about vertical pivot axes through suitable interconnecting linkage to a steering wheel 18 mounted above the rear portion of the frame in front of an operators seat 20.

An auxiliary blade-mounting frame 22, commonly referred to as a drawbar, is adjustably mounted below the arched portion of the main frame 10 and, it turn, supports the blade 60 thereunder for additional adjustments, as will become ap parent hereinafter. More particularly, the drawbar 22 is secured by a universal pivotal mount 24 to the front of the main frame 10 and extends rearwardly therefrom in a generally triangular configuration. On opposite sides of its rearward end, the drawbar 22 is pivotally secured to the lower end of adjustment-links 34 which are, in turn, pivotally secured at their upper ends to crank arms 36 which can beturned from suitable actuating linkage 38 under the control of the operator so that the drawbar can be raised or lowered and thus, in turn, effect raising or lowering of the blade 30 suspended therefrom. Preferably, as illustrated, one of the connecting links 34 takes the form of a hydraulic ram which can be extended or retracted thus to vary the transverse disposition of the drawbar 22 and, consequently, the crossslope of the blade 30 suspended therefrom. The extension or retraction of the ram is under the control of apendulum controlled valve-actuating mechanism 102 and feedback linkage is connected between the drawbar 22 and the pendulum controller mechanism 102 to indicate when a desired transverse slope of the blade 30 has bee obtained. This structure is that described in detail in US. Pat. No. 3,346,976 issued Oct.

17, 1967 to John Curlett and Raymond A. Gurries to which reference is made for details of the structure and its manner of operation.

To enable angular adjustment of the blade 30 about a vertical axis, an open ring or circle 26 is supported for rotation under the rear portion of the drawbar 22. MOre particularly, a plurality of C-shaped circle-supporting brackets 28 are integrally formed below the drawbar, as best shown in FIGS. 2 and 3, the circle 26 being adapted to rest on the lower leg portions of the C-shaped brackets for sliding movement about its own central axis. The sides of the C-shaped brackets 28 laterally confine the circle 26 and the tops of the C-shaped brackets are slightly spaced from the top of the circle so as to limit the amount of permissible lifting or vertical motion of the circle. To effect the desired rotation of the circle 26, its interior is formed with a plurality of inwardly projecting teeth so as to form an internal ring gear 32, which is arranged to mesh with a gear 34 on the shaft 36 ofa suitable hydraulic motor 38 which is under the operators control, such arrangement being conventional.

Since in normal operation of the road grader, various forces are transmitted to the blade 30, such forces are obviously transmitted also to the supporting circle 26 tending to effect continual slight vibrational shifting movement thereof within the slidable supporting brackets 28. Considerable wear is therefore experienced and is accelerated by the obvious presence of dirt and small rocks between the supporting brackets and the supported circle.

To preclude such shifting movement of the circle and the consequent wear, means are provided in accordance with the present invention to clamp the circle 26 rigidly in position on the drawbar 22 once an adjusted position of the circle has been obtained. MOre particularly, and with continued reference to FIGS. 2 and 3, a plurality of clamping levers 40 are supported under the drawbar to effect the desired rigid clamping engagement between the circle 26 and the drawbar 22, one of such levers 40 being illustrated most clearly in FIG. 3. As there shown, the lever 40 is supported a short distance from its outer end of a pivot pin 42 carried by brackets 44 depending from the under surface of the drawbar 22. When so pivotally supported the outer extremity of the lever 40 underlies the inwardly projecting ring gear portion of the circle 26, so as to be capable upon pivotal movement of the lever 40 in a clockwise direction from the position shown in FIG. 3, to urge the circle 26 upwardly into clamping engagement with the upper leg of the C-shaped bracket 28. The other end of the lever 40 is considerably longer and at its extremity is pivotally connected to the lower end of a hydraulic ram 46 which, in turn, is pivotally mounted on the drawbar 22 thereabove so that upon extension of the ram the lever 40 is brought into clamping engagement with the circle 26, and upon its retraction, the lever 40 is withdrawn sufficiently to permit the circle to drop onto the lower portion of the C-shaped bracket 28 so as to be capable of sliding rotary movement thereon. Preferably four of the levers 40 are employed to provide a balanced clamped engagement of the circle 26 and accordingly, as indicated in FIG. 6, for hydraulic rams 46 are fed simultaneously through parallel branch conduits 48 emanating from a manifold 50 centrally supported on the drawbar 22. From such manifold 50, main hydraulic conduits 52 extend forward along the drawbar to its pivotal mount 24 thence rearwardly along the main frame to a hydraulic control valve 54 adjacent to the operators seat 20, and thereafter to a suitable source of hydraulic fluid under pressure (not shown).

With additional reference to FIG. 8, the circle clamp con trol valve 54 is mounted in a control box 56 which houses a plurality of valves that are under the control of the operator through the appropriate manual manipulation of a series of control handles. The described circle clamp control valve 54 is connected to one of these handles 62 by a pivoted crank arm 58 which is urged to a valve clamping position by a coil spring 60 supported under tension between the crank arm and a fixed member in the control box. When the circle clamp control valve 54 is urged to the illustrated operative disposition by the coil spring 60, the associated handle 62 urged against the base of a T-shaped slot 64 in the top of the control box 56, but as will be obvious, the handle can be shifted to the right as viewed in FIG. 8 into the central head portion of the T-shaped slot 64 at which position, the circle clamp control valve 54 is arranged to reverse the connections to the main hydraulic conduits 52 and accordingly to all four of the hydraulic rams 46 to effect release of the clamped engagement of the circle 26. Details of the valve structure itself are not illustrated since it is of conventional nature.

When the handle 62 has been moved-into the central head portion of the T-shaped slot 64, it can be moved forwardly or rearwardly thcrewithin to effect rotation of the hydraulic motor 38 in one direction or another, thus to effect turning of the circle 26. Such forward or rearward motion of the handle 62 in the head ofthe T-shaped slot 64 is transmitted by a simple crank linkage 61 to an associated valve 68 within the control box 56 which, in turn, controls the flow of hydraulic fluid to the described motor 38. Further details ofthe hydraulic circuit and the associated motor 38 are also not described in further detail since they are of conventional nature, and take substantially the form existent on presently available road graders. It is to be expressly observed, however, that energization of the hydraulic motor 38 in either direction is impossible until the handle 62 has been removed from the base portion of the T-shaped slot 64, thus to preclude the accidental actuation of the circle drive motor without prior release of the clamping mechanism. Furthermore, if the hydraulic motor 38 is energized so that the handle 62 is not opposite the base portion of the T-shaped slot 64, the clamping mechanism cannot be actuated.

A pair of arms 70 curve downwardly from the opposite sides of the described circle 26 and carry aligned stub shafts 72 at their lower extremities to provide pivotal support for blademounting brackets 74, one of which is best illustrated in FIGS. 4 and 5. At its forward edge, each bracket 74 carries a U- shaped seat 76 adjacent its lower end and an additional retainer 78 of inverted U-shaped configuration adjacent its upper end, the two U-shaped members being arranged to confine therebetween a pair of parallel rails 80, 82 rigidly secured to the rear face of the curved grading blade 30 itself. The lower rail 80 normally rests slidably on the U-shaped seat 76 and the upper rail 82 is spaced slightly from the bottom of the inverted U-shaped retainer 78, thus to enable slidable shifting movement of the blade on the supporting brackets. In order to effect such slidable movement, a hydraulic ram 84 is disposed longitudinally of the blade 30 behind its rear face and is connected at one end to one of the brackets 74 and its opposite end to the blade 30 itself so that extension of the ram will provide movement of the blade to the right, as viewed in FIG. 5, and retraction thereof will, of course, provide for lateral shifting movement of the blade in the opposite direction or to the left, as viewed in FIG. 5. The described slidable mount for the blade 30 and the hydraulic mechanism for actuating the same is conventional and will accordingly be described in no further detail.

The brackets 74, the blade 30 supported therefrom and the hydraulic ram 84 are arranged for limited pivoted motion about the axis defined by the stub shafts 72 on the mounting arms 70 to enable a variation in the angle of blade engagement with the earth. For this purpose, hydraulic rams 86 are connected between the opposite sides of the circle 26 and the pivoted mounting brackets 74 and are arranged, again, in a conventional fashion for hydraulic extension or retraction under the control of the operator.

In accordance with the present invention, an additional clamping mechanism is provided to secure the blade 30 rigidly in its laterally adjusted position after such adjustment has been made by relative sliding movement of the blade supporting rails 80, 82 along the U-shaped seat 76 at the lower end of they supporting brackets 74. With continued reference to FIGS. 4 and 5, such clamping mechanism takes the form preferably of a simple lever 90 which is centrally mounted on the same pivot shaft 72 that mounts the blade supporting brackets 74, one end of the lever 90 extending forwardly therefrom so as to underlie the lower supporting rail 80 and the other end extending a considerable distance angularly upwardly in the opposite direction for pivotal connection to one end ofa hydraulic ram 92 whose opposite extremity is connected pivotally to the side of the supporting bracket 74. It will be understood that a similar lever and actuating ram is mounted on the bracket at the other side of the machine, as may be indicated by reference to HQ 7.

When the hydraulic rams 92 are extended, the levers 90 are caused to pivot in a counterclockwise direction, as viewed in FIG. 4, so that the lower end of the lever 90 is moved up wardly into engagement with the lowerrail 80 to thereafter lift the entire blade structure until the upper surface of the upper rail 82 is brought into clamped engagement with the under surface of the U-shaped retainer 78. Obviously such clamped engagement will be released upon retraction of the. hydraulic rams 92.

To effect the extension or retraction of the hydraulic rams 92, both rams are connected through branch hydraulic conduits 94 to a central manifold 96 on the drawbar 22, as most clearly indicated by reference to FIG. 8. In turn, main hydraulic conduits 98 extend forwardly along the drawbar to its pivotal mount 24 and thence rearwardly along the main frame to a control valve 100 located in the previously described control box 56 which valve controls the flow of hydraulic fluid under pressure from a suitable source (not shown). This blade clamping valve 100 is mechanically joined with a control handle 112 which emerges from the control box 56 through a T- shaped slot 114 similar to that described in connection with the circle clamping valve 54. In fact, the connection linkage is preferably identical to that shown and described in connection with the circle control valve so that detailed description thereof will no be repeated. Lateral movement of the handle 112 in the base portion of the T-shaped slot 114 effects retrac tion of the hydraulic rams'92 so as to release the blade for lateral sliding motion and subsequent forward or rearward movement of the handle in the head portion of the T-shaped slot 114 will effect extension or retraction of the hydraulic rams so as to slidably" shift the blade 30 on the supporting brackets 74. This forward or rearward motion of the handle 112 is transmitted toa suitable control valve not shown in a fashion similar to that described in connection with the control of the hydraulic motor 38 for the rotary motion of the circle 26 and thus its description will also not be repeated.

It will be understood that the clamping mechanisms hereinabove described as applied to a circle or blade of a conventional road grader can readily be applied to other structures wherein similar vibrational problems cause wear and thus can be overcome through use of such clamping mechanisms. Accordingly, the foregoing description of two clamping mechanisms is to be considered as purely exemplary and not in a limiting sense and the actual scope of the invention is to be indicated only be reference to the appended claims.

lclaim:

l. Clampingmechanism in combination with an adjustable working implement of a road building machine which comprises,

means including a pair of relatively movable elements adapted to support the working implement of a road building machine which comprises, means including a pair of relatively movable elements adapted to support the working implement for adjustment,

one of said elements constituting a slidably supported circle carrying the working implement and clamping means including a member movable into engagement with said circle to press the same substantially parallel to its axis rigidly against the other of said elements whereby relative vibrational motion between said elements and consequent wear are substantially eliminated in the clamped working position.

2. Clamping mechanism in combination with an adjustable working implement of a road building machine which comprises,

means including a pair of relatively movable elements adapted to support the working implement for adjustment,

means operative to clamp said elements rigidly against one another whereby relative vibrational motion of said elements and consequent wear are substantially eliminated, in the clamped working position, means for slidably adjusting said relatively movable elements, and

means including a common actuating member for said adjusting means and said clamping means movable to one position to energize said clamping means and another position to energize said adjusting means whereby operation of one of said means automatically precludes opera tion of the other.

3. Clamping mechanism in combination with an adjustable working implement of a road building machine which com' prises,

means including a pair of relatively movable elements adapted to support the working implement for adjustment, said relatively movable elements including a supporting element and a supported element slidably resting on said supporting element and having vertically opposed surfaces capable of being disposed out ofengagement, and

means operative to raise said slidably supported element to bring said nonengaging surfaces into rigid clamping engagement against one another whereby relative vibra tional motion of said elements and consequent wear are eliminated,

said relatively movable elements including a circle slidably supported on a mounting bracket, and carrying the working implement,

said mounting bracket also including a downwardly facing surface in spaced opposed relation to an surface on said circle, and said clamping means constituting means to lift said circle upwardly to bring said opposed surfaces into clamping engagement. 4. Clamping mechanism in combination with an adjustable working implement of a road building machine which comprises,

means including a pair of relatively movable elements adapted to support the working implement for adjustment, said relatively movable elements including a supporting element and a supported element slidably resting on said supporting element and having vertically opposed surfaces capable of being disposed out of engagement, and means operative to raise said slidably supported element to upwardly-facing bring said nonengaging surfaces into rigid clamping en- I FORM Po-wso (10-69:

UNETED STATES @FFECE CERTIFICATE 0? CO1 RETEN Patent No. 3,593,806 ated July 20, 1971 Invent0r(s) y d A. Gurries It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, lines 63 to 66, cancel "of a road building 5 machine which comprises, means including a pair of relatively movable elements adapted to support the working implement". Column 6, line 66, cancel "engagement with the upper bracketsf'.

Signed and sealed this 23rd day of May 1972.

I [SEAL] g Attest:

i EDWXRD M.PLETCHER,JR. ROBERT GOTTSEHALK :iAttesting Officer Commissioner of Patents 

1. Clamping mechanism in combination with an adjustable working implement of a road building machine which comprises, means including a pair of relatively movable elements adapted to support the working implement of a road building machine which comprises, means including a pair of relatively movable elements adapted to support the working implement for adjustment, one of said elements constituting a slidably supported circle carrying the working implement and clamping means including a member movable into engagement with said circle to press the same substantially parallel to its axis rigidly against the other of said elements whereby relative vibrational motion between said elements and consequent wear are substantially eliminated in the clamped working position.
 2. Clamping mechanism in combination with an adjustable working implement of a road building machine which comprises, means including a pair of relatively movable elements adapted to support the working implement for adjustment, means operative to clamp said elements rigidly against one another whereby relative vibrational motion of said elements and consequent wear are substantially eliminated, in the clamped working position, means for slidably adjusting said relatively movable elements, and means including a common actuating member for said adjusting means and said clamping means movable to one position to energize said clamping means and another position to energize said adjusting means whereby operation of one of said means automatically precludes operation of the other.
 3. Clamping mechanism in combination with an adjustable working implement of a road building machine which comprises, means including a pair of relatively movable elements adapted to support the working implement for adjustment, said relatively movable elements including a supporting element and a supported element slidably resting on said supporting element and having vertically opposed surfaces capable of being disposed out of engagement, and means operative to raise said slidably supported element to bring said nonengaging surfaces into rigid clamping engagement against one another whereby relative vibrational motion of said elements and consequent wear are eliminated, said relatively movable elements including a circle slidably supported on a mounting bracket, and carrying the working implement, said mounting bracket also including a downwardly facing surface in spaced opposed relation to an upwardly-facing surface on said circle, and said clamping means constituting means to lift said circle upwardly to bring said opposed surfaces into clamping engagement.
 4. Clamping mechanism in combination with an adjustable working implement of a road building machine which comprises, means including a pair of relatively movable elements adapted to support the working implement for adjustment, said relatively movable elements including a supporting element and a supported element slidably resting on said supporting element and having vertically opposed surfaces capable of being disposed out of engagement, and means operative to raise said slidably supported element to bring said nonengaginG surfaces into rigid clamping engagement against one another whereby relative vibrational motion of said elements and consequent wear are eliminated, said relatively movable elements including an earth moving blade having two rails attached to the rear surface thereof in substantially horizontal parallelism, and lower and upper mounting brackets slidably supporting the lower rail and in spaced relation to the upper rail respectively, and engagement with the upper brackets. said clamping means is operative to lift the said blade and attached rails so as to bring the upper rails into clamped engagement with the upper brackets. 